// Copyright (c) the JPEG XL Project Authors. All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

#include "lib/jxl/enc_ans_simd.h"

#include <cstdint>

#include "lib/jxl/base/compiler_specific.h"

#include "lib/jxl/base/status.h"

#include "lib/jxl/dec_ans.h"

#include "lib/jxl/memory_manager_internal.h"

#undef HWY_TARGET_INCLUDE

#define HWY_TARGET_INCLUDE "lib/jxl/enc_ans_simd.cc"

#include <hwy/foreach_target.h>

#include <hwy/highway.h>

HWY_BEFORE_NAMESPACE();

namespace jxl {

namespace HWY_NAMESPACE {

// These templates are not found via ADL.

using hwy::HWY_NAMESPACE::Add;

using hwy::HWY_NAMESPACE::And;

using hwy::HWY_NAMESPACE::Ge;

using hwy::HWY_NAMESPACE::GetLane;

using hwy::HWY_NAMESPACE::Gt;

using hwy::HWY_NAMESPACE::IfThenElse;

using hwy::HWY_NAMESPACE::IfThenElseZero;

using hwy::HWY_NAMESPACE::Iota;

using hwy::HWY_NAMESPACE::LoadU;

using hwy::HWY_NAMESPACE::Lt;

using hwy::HWY_NAMESPACE::Mul;

using hwy::HWY_NAMESPACE::Or;

using hwy::HWY_NAMESPACE::Set;

using hwy::HWY_NAMESPACE::ShiftRight;

using hwy::HWY_NAMESPACE::Store;

using hwy::HWY_NAMESPACE::Sub;

using hwy::HWY_NAMESPACE::Zero;

template <size_t E, size_t M, size_t L>

uint32_t EstimateTokenCostImpl(uint32_t* JXL_RESTRICT values, size_t len,

                               uint32_t* JXL_RESTRICT out) {

  const HWY_FULL(uint32_t) du;

  const HWY_FULL(float) df;

  const auto kZero = Zero(du);

  const auto kSplit = Set(du, 1 << E);

  const auto kExpOffset = Set(du, 127);

  const auto kEBOffset = Set(du, 127 + M + L);

  const auto kBase = Set(du, static_cast<uint32_t>((1 << E) - (E << (M + L))));

  const auto kMulN = Set(du, 1 << (M + L));

  const auto kMaskL = Set(du, (1 << L) - 1);

  const auto kMaskM = Set(du, ((1 << M) - 1) << L);

  const auto kLargeThreshold = Set(du, (1 << 22) - 1);

  constexpr size_t kLargeShiftVal = 10;

  const auto kLargeShift = Set(du, kLargeShiftVal);

  auto extra_bits = kZero;

  size_t last_full = Lanes(du) * (len / Lanes(du));

  for (size_t i = 0; i < last_full; i += Lanes(du)) {

    const auto val = LoadU(du, values + i);

    const auto is_large = Gt(val, kLargeThreshold);

    const auto val_shifted = ShiftRight<kLargeShiftVal>(val);

    const auto not_literal = Ge(val, kSplit);

    const auto val_fixed = IfThenElse(is_large, val_shifted, val);

    const auto b = BitCast(du, ConvertTo(df, val_fixed));

    const auto l = And(val, kMaskL);

    const auto exp = ShiftRight<23>(b);

    const auto exp_fixed = IfThenElse(is_large, Add(exp, kLargeShift), exp);

    const auto n = Sub(exp_fixed, kExpOffset);

    const auto eb = Sub(exp_fixed, kEBOffset);

    const auto m = ShiftRight<23 - M - L>(b);

    const auto a = Add(kBase, Mul(n, kMulN));

    const auto d = And(m, kMaskM);

    const auto eb_fixed = IfThenElseZero(not_literal, eb);

    const auto c = Or(a, l);

    extra_bits = Add(extra_bits, eb_fixed);

    const auto t = Or(c, d);

    const auto t_fixed = IfThenElse(not_literal, t, val);

    Store(t_fixed, du, out + i);

  }

  if (last_full < len) {

    const auto stop = Set(du, len);

    const auto fence = Iota(du, last_full);

    const auto take = Lt(fence, stop);

    const auto val = LoadU(du, values + last_full);

    const auto is_large = Gt(val, kLargeThreshold);

    const auto val_shifted = ShiftRight<kLargeShiftVal>(val);

    const auto not_literal = Ge(val, kSplit);

    const auto val_fixed = IfThenElse(is_large, val_shifted, val);

    const auto b = BitCast(du, ConvertTo(df, val_fixed));

    const auto l = And(val, kMaskL);

    const auto exp = ShiftRight<23>(b);

    const auto exp_fixed = IfThenElse(is_large, Add(exp, kLargeShift), exp);

    const auto n = Sub(exp_fixed, kExpOffset);

    const auto eb = Sub(exp_fixed, kEBOffset);

    const auto m = ShiftRight<23 - M - L>(b);

    const auto a = Add(kBase, Mul(n, kMulN));

    const auto d = And(m, kMaskM);

    const auto eb_fixed = IfThenElseZero(not_literal, eb);

    const auto eb_masked = IfThenElseZero(take, eb_fixed);

    const auto c = Or(a, l);

    extra_bits = Add(extra_bits, eb_masked);

    const auto t = Or(c, d);

    const auto t_fixed = IfThenElse(not_literal, t, val);

    Store(t_fixed, du, out + last_full);

  }

  return GetLane(SumOfLanes(du, extra_bits));

}

uint32_t EstimateTokenCost(uint32_t* JXL_RESTRICT values, size_t len,

                           HybridUintConfig cfg, AlignedMemory& tokens) {

  uint32_t* JXL_RESTRICT out = tokens.address<uint32_t>();

#if HWY_TARGET == HWY_SCALAR

  uint32_t extra_bits = 0;

  for (size_t i = 0; i < len; ++i) {

    uint32_t v = values[i];

    uint32_t tok, nbits, bits;

    cfg.Encode(v, &tok, &nbits, &bits);

    extra_bits += nbits;

    out[i] = tok;

  }

  return extra_bits;

#else

  if (cfg.split_exponent == 0) {

    return EstimateTokenCostImpl<0, 0, 0>(values, len, out);

  } else if (cfg.split_exponent == 2) {

    JXL_DASSERT((cfg.msb_in_token == 0) && (cfg.lsb_in_token == 1));

    return EstimateTokenCostImpl<2, 0, 1>(values, len, out);

  } else if (cfg.split_exponent == 3) {

    if (cfg.msb_in_token == 1) {

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<3, 1, 0>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 2);

        return EstimateTokenCostImpl<3, 1, 2>(values, len, out);

      }

    } else {

      JXL_DASSERT(cfg.msb_in_token == 2);

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<3, 2, 0>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 1);

        return EstimateTokenCostImpl<3, 2, 1>(values, len, out);

      }

    }

  } else if (cfg.split_exponent == 4) {

    if (cfg.msb_in_token == 1) {

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<4, 1, 0>(values, len, out);

      } else if (cfg.lsb_in_token == 2) {

        return EstimateTokenCostImpl<4, 1, 2>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 3);

        return EstimateTokenCostImpl<4, 1, 3>(values, len, out);

      }

    } else {

      JXL_DASSERT(cfg.msb_in_token == 2);

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<4, 2, 0>(values, len, out);

      } else if (cfg.lsb_in_token == 1) {

        return EstimateTokenCostImpl<4, 2, 1>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 2);

        return EstimateTokenCostImpl<4, 2, 2>(values, len, out);

      }

    }

  } else if (cfg.split_exponent == 5) {

    if (cfg.msb_in_token == 1) {

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<5, 1, 0>(values, len, out);

      } else if (cfg.lsb_in_token == 2) {

        return EstimateTokenCostImpl<5, 1, 2>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 4);

        return EstimateTokenCostImpl<5, 1, 4>(values, len, out);

      }

    } else {

      JXL_DASSERT(cfg.msb_in_token == 2);

      if (cfg.lsb_in_token == 0) {

        return EstimateTokenCostImpl<5, 2, 0>(values, len, out);

      } else if (cfg.lsb_in_token == 1) {

        return EstimateTokenCostImpl<5, 2, 1>(values, len, out);

      } else if (cfg.lsb_in_token == 2) {

        return EstimateTokenCostImpl<5, 2, 2>(values, len, out);

      } else {

        JXL_DASSERT(cfg.lsb_in_token == 3);

        return EstimateTokenCostImpl<5, 2, 3>(values, len, out);

      }

    }

  } else if (cfg.split_exponent == 6) {

    if (cfg.msb_in_token == 0) {

      JXL_DASSERT(cfg.lsb_in_token == 0);

      return EstimateTokenCostImpl<6, 0, 0>(values, len, out);

    } else if (cfg.msb_in_token == 1) {

      JXL_DASSERT(cfg.lsb_in_token == 5);

      return EstimateTokenCostImpl<6, 1, 5>(values, len, out);

    } else {

      JXL_DASSERT(cfg.msb_in_token == 2);

      JXL_DASSERT(cfg.lsb_in_token == 4);

      return EstimateTokenCostImpl<6, 2, 4>(values, len, out);

    }

  } else if (cfg.split_exponent >= 7 && cfg.split_exponent <= 12) {

    JXL_DASSERT(cfg.msb_in_token == 0);

    JXL_DASSERT(cfg.lsb_in_token == 0);

    if (cfg.split_exponent == 7) {

      return EstimateTokenCostImpl<7, 0, 0>(values, len, out);

    } else if (cfg.split_exponent == 8) {

      return EstimateTokenCostImpl<8, 0, 0>(values, len, out);

    } else if (cfg.split_exponent == 9) {

      return EstimateTokenCostImpl<9, 0, 0>(values, len, out);

    } else if (cfg.split_exponent == 10) {

      return EstimateTokenCostImpl<10, 0, 0>(values, len, out);

    } else if (cfg.split_exponent == 11) {

      return EstimateTokenCostImpl<11, 0, 0>(values, len, out);

    } else {

      return EstimateTokenCostImpl<12, 0, 0>(values, len, out);

    }

  } else {

    JXL_DASSERT(false);

  }

  return ~0;

#endif

}

// NOLINTNEXTLINE(google-readability-namespace-comments)

}  // namespace HWY_NAMESPACE

}  // namespace jxl

HWY_AFTER_NAMESPACE();

#if HWY_ONCE

namespace jxl {

HWY_EXPORT(EstimateTokenCost);

uint32_t EstimateTokenCost(uint32_t* JXL_RESTRICT values, size_t len,

                           HybridUintConfig cfg, AlignedMemory& tokens) {

  JXL_DASSERT(cfg.lsb_in_token + cfg.msb_in_token <= cfg.split_exponent);

  return HWY_DYNAMIC_DISPATCH(EstimateTokenCost)(values, len, cfg, tokens);

}

}  // namespace jxl

#endif